In this video I show how to subtract integers by using counters. The counters help you visualize the process of subtracting integers. If you struggle with remembering how to subtract positive and negative numbers,this video will help.
Welcome to MooMooMath and subtracting integers.
Subtracting Integers using counting chips
You have two options when solving these problems.
When subtracting you can represent each number following the subtraction sign with a zero pair and then work the problem with the counting chips or…
You can change the subtraction sign to addition and change the sign of the number right after the subtraction sign.
Let’s look at some example problems.
In this video I would like to talk about subtracting integers that are positive and negative.
In order to do that I'm going to use counters and I don't have counters but I will use nickels and pannies.
The nickel will be positive because it is better to get 5 cents instead of a penny. The penny will be the negative number.
When you have a positive and negative number together they cancel each other and we will call this a zero pair.
Whenever we have 4- -3 we may get confused about subtracting the negative. I will show you two techniques for solving this problem.
You can decide which one you like best.
I will first put down four positive numbers.
When I go to subtract a negative 3 there is nothing to subtract.
What some people do is let a zero pair represent a negative number.
So I will place a zero pair and I will place three zero pairs.
I can now subtract the negative numbers, and I'm left with 1 2 3 4 5 6 7 positives.
The method I prefer, but you can use either one is that when you subtract a negative number you change the subtraction sign to positive and change the sign of the number directly behind the subtraction sign.
Now I will use my counters and place 4 positives and 3 more positives. You can see that I now have 7 positive numbers.
Let's work the next one.
You have -3 - 4
I will begin by putting down 3 negative chips.
Now I need to subtract 4, but I don't have 4 to subtract.
I will put down a zero pair for each -4. I will put down 4 zero pairs.Here is my fourth zero pair.
I subtract 4 positive, and I'm left with 1 2 3 4 5 6 7 negative numbers.
I prefer the second method.
I have a negative number and subtraction.
I will change subtraction to addition, and change the sign of the number directly behind the subtraction.
I put down 3 negatives, and four negatives here and I'm left with 1 2 3 4 5 6 7 negative numbers.
Let's work 5 - negative 2
I will change the subtraction to a positive, and change the sign of the number behind the subtraction.
I will 5 counters for the first number which is 5, and 2 counters for the 2.
This gives me 1 2 3 4 5 6 7 which equals positive 7
Let's work the last example.
We have 2 - a negative 3
Before I get started if you have a test and like the counters you can literally get a sheet of paper and write a positive on one sheet and negative on the other.These would work as counters. If you like the counters you can make some homemade counters and use these on the test or quiz.
I like to just change the sign.
I have a negative number and subtraction.
I will go 2 change the sign to positive.
Change the sign of the number directly behind it.
It becomes a positive 3
I will place the counters down, my nickel is positive so I will put 2 for this side, and 3 n the other side.
When I total that I get 5
If you don't like that method you can put down 3 zero pairs for the negative number.
Next I will subtract the negative you get the same answer.
Hope this helps with subtracting integers. MooMooMath uploads a new math video everyday.
Please watch: "Study Skills Teacher's Secret Guide to your Best Grades"
Tagged under: math,integers,subtracting,subtracting integers,numbers,moomoomath,counters,counting chips
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